Infertility rates are rising and nobody seems to quite know why. Below is what feels like a possible (trivial) explanation that I haven’t seen mentioned anywhere.
I’m not in this field personally so it’s possible this theory is out there, but asking GPT about it doesn’t yield the proposed explanation: https://chat.openai.com/share/ab4138f6-978c-445a-9228-674ffa5584ea
Toy model:
a family is either fertile or infertile, and fertility is hereditary
the modal fertile family can have up to 10 kids, the modal infertile family can only have 2 kids
in the olden days families aimed to have as many kids as they could
now families aim to have 2 kids each
Under this model, in the olden days we would find a high proportion of fertile people in the gene pool, but in the modern world we wouldn’t. Put differently, the old convention lead to a strong positive correlation between fertility and participation in the gene pool, and the new convention leads to 0 correlation. This removes the selective pressure on fertility, hence we should expect fertility to drop / infertility to rise.
Empirical evidence for this would be something like an analysis of the time series of family size variance and infertility—is lower variance followed by increased infertility?
Pretending not to see when a rule you’ve set is being violated can be optimal policy in parenting sometimes (and I bet it generalizes).
Example: suppose you have a toddler and a “rule” that food only stays in the kitchen. The motivation is that each time food is brough into the living room there is a small chance of an accident resulting in a permanent stain. There’s cost to enforcing the rule as the toddler will put up a fight. Suppose that one night you feel really tired and the cost feels particularly high. If you enforce the rule, it will be much more painful than it’s worth in that moment (meaning, fully discounting future consequences). If you fail to enforce the rule, you undermine your authority which results in your toddler fighting future enforcement (of this and possibly all other rules!) much harder, as he realizes that the rule is in fact negotiable / flexible.
However, you have a third choice, which is to credibly pretend to not see that he’s doing it. It’s true that this will undermine your perceived competence, as an authority, somewhat. However, it does not undermine the perception that the rule is to be fully enforced if only you noticed the violation. You get to “skip” a particularly costly enforcement, without taking steps back that compromise future enforcement much.
I bet this happens sometimes in classrooms (re: disruptive students) and prisons (re: troublesome prisoners) and regulation (re: companies that operate in legally aggressive ways).
Of course, this stops working and becomes a farce once the pretense is clearly visible. Once your toddler knows that sometimes you pretend not to see things to avoid a fight, the benefit totally goes away. So it must be used judiciously and artfully.